Generating a Comprehensive Climate Change Streamflow Scenarios

Database for the Columbia River Basin

Alan F. HamletKurt Unger Philip W. MoteEric SalathéDennis P. Lettenmaier

JISAO/CSES Climate Impacts GroupDept. of Civil and Environmental EngineeringUniversity of WashingtonWA State Department of Ecology

Image Credit: National Snow and Ice Data Center, W. O. Field, B. F. Molniahttp://nsidc.org/data/glacier_photo/special_high_res.html

Aug, 13, 1941 Aug, 31, 2004

Recession of the Muir Glacier

March 5, 2002

Collapse of theLarsen B Ice shelf,Antarctica

Mote P.W.,Hamlet A.F., Clark M.P., Lettenmaier D.P., 2005, Declining mountain snowpack in western North America, BAMS, 86 (1): 39-49

Trends in April 1 SWE 1950-1997

Overview of 21st Century Climate Projections and Some Water Resources Impact Pathways

Pacific Northwest

°C

0.4-1.0°C0.9-2.4°C 1.2-5.5°C

Obse

rved 2

0th

centu

ry v

ari

abili

ty

+1.7°C+0.7°C

+3.2°C

Pacific Northwest

% -1 to +3%

-1 to +9% -2 to +21%

Obse

rved 2

0th

centu

ry v

ari

abili

ty

+1% +2%

+6%

0

20

40

60

80

100

120

oct nov dec jan feb mar apr may jun jul aug sep

Sim

ula

ted

Bas

in A

vg R

un

off

(m

m)

1950

plus2c

Simulated Changes in Natural Runoff Timing in the Naches River Basin Associated with 2 C Warming

Impacts:•Increased winter flow•Earlier and reduced peak flows•Reduced summer flow volume•Reduced late summer low flow

Water Supply and Demand

•Changes in the seasonality water supply (e.g. reductions in summer)

•Changes in water demand (e.g. increasing evaporation)

•Changes in drought stress

•Increasing conflicts between water supply and other uses and users of water

Energy Supply and Demand

•Changes in the seasonality and quantity of hydropower resources

•Changes in energy demand

•Increasing conflicts between hydro and other uses and users of water

Instream Flow Augmentation

•Changes in low flow risks

•Changes in the need for releases from storage to reproduce existing streamflow regime.

•Changes in water resources management related to water quality (e.g. to provide dilution flow or to control temperature)

Flood Control and Land Use Planning

•Changes in flood risks

•Changes in flood control evacuation and timing

•Dam safety

Impacts in Estuaries

•Impacts of sea level rise and changing flood risk on low lying areas (dikes and levies)

•Impacts to ecosystem function

•Changes in land use policy (coastal armoring, land ownership, FEMA maps)

Long-Term Planning, Water Resources Agreements, Water Law and Policy

•Water allocation agreements in a non-stationary climate (e.g. water permitting)

•Appropriateness of the historic streamflow record as a legal definition of climate variability

•Need for new planning frameworks in a non-stationary climate

•Transboundary implications for the Columbia Basin

As the public and professionals in the water management and policy arenas have become increasing concerned about the impacts of climate change on PNW water resources, demand for hydrologic scenarios suitable for planning purposes at a range of spatial scales has increased dramatically.

Currently there does not exist an up-to-date, comprehensive, and self-consistent data base of hydrologic scenarios for the Columbia River basin that is suitable for the range of planning activities the Climate Impacts Group is being asked to support.

A Need to Provide Improved Access to Hydrologic Scenarios for Planning

Study Overview

Collaboration with WA Department of Ecology and Regional Stakeholders to Provide Improved Access to Hydrologic Scenarios in the Columbia River Basin

Funding Source: House Bill 2860

•$16 Million for studies related to enhancing water supplies in the Columbia River basin for irrigation and municipal water supply.

•Up to $200 Million for implementing improvements identified by these studies.

Answers to FAQ regarding WA 2860 from the Department of Ecology website:

http://www.ecy.wa.gov/pubs/0611014.pdf

Regional Study Partners

•WA State Department of Ecology

•Bonneville Power Administration

•Northwest Power and Conservation Council

•State of Oregon

•Province of British Columbia (BC Hydro and The Ministry of Environment)

Streamflow Data Needs to Support a 21st Century Planning Framework Incorporating Climate Information and Uncertainty

2 Emissions Scenarios

20 GCM Scenarios

2 Downscaling Approaches

X

X

2 Hydro. Modeling ApproachesX

= Up to 160 realizations of future streamflow variability at each location!

The Need to Encompass Multiple Spatial Scales

Large Scale Planning Studies

Examples:

•Hydro System Performance•Flood Control•Main Stem ESA•Transboundary Issues•Large-Scale Irrigation Impacts

WA State Water Resources Inventory Areas

Medium Scale Planning Studies

Examples:

Water Supply Planning

•Yakima Basin•Okanogan Basin•Methow•Walla Walla Basin

Snow Model

Schematic of VIC Hydrologic Model and Energy Balance Snow Model

PNW1/16th

Deg.

6 km

6 km

Alternate Approach: DHSVMDeveloped in the

UW Land Surface

Hydrology Research

Group at UW, the model has been used for over a decade in hydrologic research applications associated with small catchments.

DHSVM: Distributed Hydrology-Soil-Vegetation Model

Blue = Large Scale Planning Sites

Green = Snake River Sites

Red = Additional Sites in WA

Partnerships with the BPA, NWPCC, OR and BC will extend the number of sites included in the study to support specific planning activities in these areas. The UW will also collaborate informally with the U of I.

Streamflow Locations Currently Under Consideration

On-Line Survey Website, Project Scope

http://cses.washington.edu/cig/http://www.surveymonkey.com/s.aspx?sm=daSOYBVOb238oFy6ia7bcA_3d_3d